슬라이드 1

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1 고분자몰폴로지 Huh, PilHo Department of Polymer Science and Engineering

편광현미경 (Polarized optical microscope, POM) 편광 :

회전하는재물대상하에각각일정한방향으로진동하는빛만을통과시키는편광판 2 개가부착.

빛을투과시키지않는물질 : 광원을위에서주어이에반사되는빛에의해 morphology 를관찰.

최대배율 : 400X ; 100X, 200X 의대물렌즈가시판, 더높은배율가능.

2 편광현미경 (Polarized optical microscope, POM) 편광 : 편광판을통과한빛과같이한쪽방향으로만진동하는빛. 회전하는재물대상하에각각일정한방향으로진동하는빛만을통과시키는편광판 2 개가부착. 위편광판을뺀상태를개방니콜 ; 끼운상태를직교니콜. 빛을투과시키지않는물질 : 광원을위에서주어이에반사되는빛에의해 morphology 를관찰. 빛을투과시키는물질 : 광원이아래에서들어와물질을투과한빛으로 morphology 를관찰. Blight Face (BF) & Dark Face (DF) 상. BF : 밝은부분을더밝게보이도록하는설정. DF : 밤하늘에서별을관찰하는것과같이배경이검을경우사용. 대물렌즈 : 5X, 10X, 20X ; 접안렌즈 : 10X ; 1X, 1.25X, 2X. 최대배율 : 400X ; 100X, 200X 의대물렌즈가시판, 더높은배율가능. Neither crystalline nor amorphous region absorbs significant amount of light No contrast generated. Contrast is introduced by polarizing POM can also measure birefringence (Δn) of transparent oriented polymer. Department of Polymer Science and Engineering 2

3 편광과복굴절 (Polarization and Birefringence) 1) Light 빛 = 파동 = 전기장 (electric field) 과자기장 (magnetic field) 은서로수직. Both fields are oscillating while they are propagating. Electromagnetic (EM) wave is propagating along z-direction. 전기장은항상 x 축과평행하고, 자기장은항상 y 축과평행. 전자기파의특성 : EM field is periodic. Oscillate only in one direction (linearly polarized) : polarization direction = electric field direction The wave is polarized in x direction. Polarization of light ; Polarization of sample (dielectric) EM wave vs wavelength (λ) : Department of Polymer Science and Engineering 3

4 2) Polarizer : 편광상태가무질서하게섞여있는 " 편광안된빛 " 에서특정한방향으로의선형편광된빛을선택적으로투과시키는광학기구를편광자. 검광자 (analyzer) : 편광자를빛의편광상태를검증하는용도로쓴다는의미에서. * 말러스 (Malus) 법칙 * 편광되지않은빛 편광방향 편광기수직편광된빛 Department of Polymer Science and Engineering 4

5 3) Polarization 1 A third test charge(+) in the fields of two positive charges A B One electric field (due to charge1) is parallel to y axis and the other (due to charge2) to x axis. Force exerted by charge1 F 1. Force exerted by charge2 F 2. The total force = F 1 + F 2. The force is a vector having magnitude and direction. 2 두전하에의한공간의한점에서의전기장 E 1 은전하 1 에의한전기장이며, E 2 는전하 2 에의한전기장임. 전체전기장은 (E 1 과 E 2 의합 ) 은에묘사되어짐. E 1 // x, E 2 // y. A B Department of Polymer Science and Engineering 5

6 3 Classification of Polarization Linear Polarization : 자기장은항상전기장진행방향과수직하면서아래그림처럼전기장 - 자기장진행방향이오른손좌표계를이루게되어야함. 더구나자기장의크기도전기장의크기와비례하므로빛의편광상태를말할때에는자기장의배치는전적으로무시하는편광. Circular Polarization : x 와 y 의두선편광이같은진폭으로, 90 o 의위상차이를가지고합성되는경우. X 방향이 90 도앞서가면우선원편광 빛을보면시계방향으로회전. Y 방향이 90 도앞서가면좌선원편광 회전하는방향이반대가되어다가오는빛을보면반시계방향으로회전. Department of Polymer Science and Engineering 6

7 Department of Polymer Science and Engineering 7

8 Elliptical Polarization : 빛이진행하는방향에대해수직면으로진동하는전기장의두성분이적절한위상차를가질수있고, 아울러진폭도서로다른값을가질수있어합성된결과. Department of Polymer Science and Engineering 8

4) Birefringence : 결정체로서그모양이대칭이아니라면빛의진행방향, 빛의편광상태에따라빛의전파속도가다를수있음.

이러한물질은한방향으로진행하는빛에대해서두가지편광상태각각속도가다른값으로주어짐. 이러한현상을복굴절이라하며, 이러한특성을갖는결정을복굴절체라함.

$전자기파동의진동이그것의진행을지연시키는매질전하를진동시킴 매질에서빛의속도가줄어듦 refractive index (n).$

9 4) Birefringence : 결정체로서그모양이대칭이아니라면빛의진행방향, 빛의편광상태에따라빛의전파속도가다를수있음. 이는원자들이대칭으로배열되어있지않아결정을이루는전자나원자의진동도운동방향에따라진동의양상이다르게나타나기때문. 이러한물질은한방향으로진행하는빛에대해서두가지편광상태각각속도가다른값으로주어짐. 이러한현상을복굴절이라하며, 이러한특성을갖는결정을복굴절체라함. Interaction of light with surrounding 진공에서는매질과빛사이에상호자용이존재하지않음. 전자기파동의진동이그것의진행을지연시키는매질전하를진동시킴 매질에서빛의속도가줄어듦 refractive index (n). Refractive index (n) : refraction of light at the interface between two media. Department of Polymer Science and Engineering 9

10 Snell s Law : 빛이등방성물질에입사될때 전기장의일부분은반사되고, 다른부분은계면을통해굴절되며 반사는입사광의편광에의존, 굴절각은두물질의굴절률에의존. [ 입사각과굴절각의사인값의비는굴절률의비의역수 ] Department of Polymer Science and Engineering 10

11 5) POM Observation of Spherulite Department of Polymer Science and Engineering 11

12 Polarization of light : Analyzator parallel to the polarizor Department of Polymer Science and Engineering 12

13 Wide Angle X-Ray Scattering (WAXS) WAXS and small angle X-ray scattering (SAXS) are both branches of the general area of scattering (materials interacting with electromagnetic radiation). In order to detect objects of a particular size radiation of comparable or smaller wavelength than the object. Object sizes : from 1Å to 1,000Å or 0.1nm to 100nm the electromagnetic radiation used for such studies is X-rays, whose wavelength is on the order of angstroms. To observe scattering from spherulites or from whole single crystals whose dimensions are on the micron scale we would use optical light. If we are looking for scattering from aircraft which are many meters in length we would use radio waves. X-ray scattering is used to determine a number of important material characteristics, for polymers these included :-. Using WAXS : SAXS measures : Department of Polymer Science and Engineering 13

14 Unit Cells Location of planes within a crystal : Miller Indices. The top view of a portion of a polymer crystal : A side view of the crystal and the same unit cell. These two views are combined to give a 3D representation of the crystal; where chains in a unit cell can be identified. Department of Polymer Science and Engineering 14

Unit cell : a, b and c dimensions and angles α, β, and γ between x, y and z

15 It s normal to just identify the final unit cell by reporting dimensions and angles. Unit cell : a, b and c dimensions and angles α, β, and γ between x, y and z axes. an abbreviated way of describing the space filling model of a crystal. lattice points a motif. Department of Polymer Science and Engineering 15

16 lattice point : 결정구조에서동일한환경을가진점들. unit cell ( 단위세포 ) : - 8 개의 lattice point 들이모인결정구조의최소단위. - 삼차원이동에의해규칙적모형이반복되는결정의기본단위. seven crystal system : - cubic, tetragonal, orthorhombic, hexagonal, trigonal, monoclinic, triclinic - 육면체가변의반복길이 a, b, c 그리고그들사이의각 α, β, γ 의여섯개인자를중심으로결정분류. system Axial lengths and angles Bravais lattice 등축정계 (Cubic) 정방정계 (Tetragonal) 사방정계 (Orthorhombic ) 육방정계 (Hexagonal) 3 축이직각이고길이도모두같다. a=b=c, α=β=γ=90 3 축이직각이고두길이는같다. a=b c, α=β=γ=90 3 축이직각이고두길이는모두틀린다. a b c, α=β=γ= 로두축길이가같고세번째축은이들과직각이다. a=b c, α=β=90, γ=120 Simple Body-centered Face-centered Simple Body-centered Simple Body-centered Base-centered Face-centered Simple 삼방정계 (Trigonal) 단사정계 (Monoclinic) 삼사정계 (Triclinic) 3 축이모두 90 가아니면서같은각이고길이는모두같다. a=b=c, α=β=γ 90 한쌍의각은직각이고 3 축의길이가틀린다. a b c, α=γ=90 β 3 축이모두직각이아니고길도틀린다. a b c, α β γ 90 Simple Simple Body-centered simple Department of Polymer Science and Engineering 16

17 14 개 Bravais 격자모형 정방정, 단순격자정방정, 체심격자 6 방정능면체정 3 사정, 단순격자단사정, 단순격자단사정, 저심격자 입방정, 단순격자 입방정, 면심격자 입방정, 체심격자 사방정, 단순격자사방정, 저심격자사방정, 면심격자사방정, 체심격자 Department of Polymer Science and Engineering 17

18 대표적인고분자구조 폴리에틸렌 사방정형구조 : planar zigzag 사슬두개가거의 90 도의각도에서 herringbone 형충전구조. setting angle : 거의 44 도. 온도상승 : 실온부근을중심으로단위격자 a 축의길이가늘어나고 setting angle 이커짐. 전단응력 : 사방정형 삼사정형 ( 가역적생성 ). 폴리프로필렌 주사슬에대한메틸기의배향. ipp, spp, app. ipp 의분자사슬 : 결정영역에서세개의모노머단위가 1 회전하는나선구조. Department of Polymer Science and Engineering 18

에틸렌 / 비닐알코올공중합체는랜덤하게결합된공중합체이지만어떤조성의시료도결정성을가짐. 폴리옥시메틸렌 안정한삼방정형과불안정한사방정형의결정이존재.

19 폴리비닐알코올 planar zigzag 사슬이충전되어분자간의수소결합이형성. atactic 으로 OH 기는 zigzag plane 바깥쪽좌우로향함. 에틸렌 / 비닐알코올공중합체는랜덤하게결합된공중합체이지만어떤조성의시료도결정성을가짐. 폴리옥시메틸렌 안정한삼방정형과불안정한사방정형의결정이존재. X- 선회절패턴은동일하지만, 적외선흡수스펙트럼은다른패턴을보임. 방향족을포함하는폴리에스터 PET 는거의 trans 형구조, PTT 는 large zigzag 구조. PTMT 는두종류의결정형구조. Department of Polymer Science and Engineering 19

인접한평면지그재그사슬이수소결합으로판상을형성, 서로 van der Waals로약하게중첩.

20 강유전성고분자 PVDF : 모든 CF 2 기가평형배열한극성결정. PVDF 필름을고전압처리 (poling) 필름전체가극성. 강유전체는고온에서상유전체 ( 무극성구조 ) 로전이. 지방족폴리아마이드 나일론 mn- 및 m- 은거의 planar zigzag 구조. 인접한평면지그재그사슬이수소결합으로판상을형성, 서로 van der Waals로약하게중첩. m-이홀수인나일론은아마이드결합 C=O기가모두동일방향으로배향, 극성이다. 강직고분자 거의직선형의구조. 분자사슬은서로수직으로수소결합. Department of Polymer Science and Engineering 20

결정평면과 Miller indices Index (hkl) : 결정내에존재하는임의의 plane

$절단분율 (fractions of intersection) (1/h, 1/k, 1/l) 의역수$ (reciprocal) (hkl). - 단위세포의임의의축에평행한평면 축과무한대에서만남 0.

21 결정평면과 Miller indices Index (hkl) : 결정내에존재하는임의의 plane 을나타내는방법. Miller 지수 : - 단위세포의변 a 를 1/h, b 를 1/k, c 를 1/l 절단한평면 절단분율 (fractions of intersection) (1/h, 1/k, 1/l) 의역수 (reciprocal) (hkl). - 단위세포의임의의축에평행한평면 축과무한대에서만남 0. - 단위세포의각축과음의방향에서절단을이루는평면 Miller 지수위에 bar 그어그평면의방향을나타냄. Interplanar spacings : 단위세포의원점으로부터임의의평면 (hkl) 까지의수직거리또는 (hkl) 평면간의수직거리 [ d-spacing or d hkl ]. Department of Polymer Science and Engineering 21

Crystallinity Density method : - degree of crystallinity

$(1) volume % crystallinity X-ray Diffraction (XRD) :$ amorphous 한고무의밀도 : 910Kg/m 3 결정화된시료의밀도 : 937Kg/m 3 Φ c of

22 Crystallinity Density method : - degree of crystallinity is quantified based on density. (1) volume % crystallinity X-ray Diffraction (XRD) : 천연고무의결정화도측정 : 이론적인 100% 결정화된고무의밀도 : 1000Kg/m 3 100% amorphous 한고무의밀도 : 910Kg/m 3 결정화된시료의밀도 : 937Kg/m 3 Φ c of rubber crystallinity =??? (2) weight % crystallinity Department of Polymer Science and Engineering 22

$- X-ray Diffraction of n- Alkanes and Polyethylene XRD 기본원리 : Bragg 의법칙 - 면간거리와파장간의관계 - 면간거리, 격자상수및면지수의관계 - 입사각과면지수의관계,, 특징 - 시료에대한제한이적다. - 시료를파괴하지않고검사를수행한다. - 시편의형태에구애받지않는다.$ $Calculation of crystallinity : - crystallinity : separating intensities due to amorphous and crystalline phase on diffraction phase.$

23 - X-ray Diffraction of n- Alkanes and Polyethylene XRD 기본원리 : Bragg 의법칙 - 면간거리와파장간의관계 - 면간거리, 격자상수및면지수의관계 - 입사각과면지수의관계,, 특징 - 시료에대한제한이적다. - 시료를파괴하지않고검사를수행한다. - 시편의형태에구애받지않는다. - 판상, 액상, 분말, 리본, 박막등 - 표준물질의데이터와비교하여물질을구분할수있다. - 결정면간거리를정확하게측정할수있다. Calculation of crystallinity : - crystallinity : separating intensities due to amorphous and crystalline phase on diffraction phase. - computer aided curve resolving technique is used to separate crystalline and amorphous phases of diffracted graph. Percentage of crystallinity Χ c % : ratio of crystalline area to total area. A c = Area of crystalline phase A a = Area of amorphous phase Χ c = Percentage of crystallinity Department of Polymer Science and Engineering 23

PowerPoint 프레젠테이션

PowerPoint 프레젠테이션 Chapter Radar Cross Section ( R C S ) 엄효준교수 한국과학기술원 Contents.1. RCS Definition.. RCS Prediction Methods.3. RCS Dependency on Aspect Angle and Frequency.4. RCS Dependency on Polarization.5. RCS of Simple